governing the values of goods, and the causes governing the value of money, are sufficiently independent to justify us in studying each separately, in abstraction, on the assumption that the other is unchanged. Hence, supply and demand, cost of production, and the other price theories, which assume a fixed value of money, are proper tools of thought for the study of the prices of goods. CHAPTER XVI THE QUANTITY THEORY AND INTERNATIONAL GOLD MOVEMENTS The quantity theory explanation of international gold movements is as follows: if money comes into a country, it raises prices. If the price-level of the country is raised more rapidly than the price-levels of other countries are rising, then the country becomes a bad place in which to buy and a good place in which to sell; its exports fall off, its imports increase, and finally the inflow of money is checked, and, perhaps, money flows out again. The equilibrium of the gold supplies of different countries is thus dependent on the price-levels of the countries involved. The quantity of gold in a country determines its price-level, and no more gold can stay in a country, on this theory, than that amount which keeps its price-level in proper relation to the price-levels of other countries. It is not necessarily asserted that the price-levels of all countries must be equal--the facts too obviously contradict that. But when this precise statement is not made, the substitute statement of some "normal" relation between the price-level of one country and that of another becomes a very vague one, and the theory becomes pretty indefinite. I am here concerned chiefly with one contention: the price-_level_, the average of prices, is not a _cause_ of anything--not of gold movements or anything else. It is a mere summary of many concrete prices. Some of these concrete prices have highly important influence on international gold movements, tending, if they are low, to bring gold in, and if they are high, to repel gold. Others work in the opposite direction, tending if they are low to attract less gold than if they are high. Finally, among all the prices affecting international gold movements, the one which is most significant is commonly not included in the price-level at all: I refer to the "price of money," the short-time interest rate.